37 



the actual banks of the streams a number of fine shady trees are found 

 which are in full leaf in August, and here the tsetses congregate. On 

 the hills around, the forest is leafless and affords but little shade. 

 Puparia, for the most part empty, were found at the bases of the shady 

 trees, mostly on sharply sloping ground, but not invariably. 



" Searching in the leaf mould, etc., beneath bushes on the banks of 



the river, near the trees where the pupae were found, again proved 



fruitless at Sinombi, and this, coupled with the results at Manzituba 



and the very prolonged searches made in such situations near the Gorai 



River, Lomagundi, in November and April, leads me to the opinion 



, that such spots are rarely, if ever, selected for the deposition of the 



'larvae. The tsetse-fly is such a comparatively slow breeder that it 



can scarcely afford to expose its pupae to the scratchings of the game 



birds which frequent exactly the same haunts as the fly during the dry 



weather, and often in amazing numbers. Along the Gorai River in 



.November the numbers of guinea fowl, 'pheasant' (Pternistes) and 



^'redwing' (Francolinus) were astonishing. They rose at almost 



every step along the banks, and all the ground under the bushes had 



been scratched over and over again." 



On the other hand, Professor Newstead, F.R.S. (107), writing on 

 the bionomics of Glossina morsitans, as observed by himself and 

 i Dr. J. B. Davey in 191 1 in Nyasaland, in a district near the Shire River, 

 about four miles south of Lake Malombe, states : " The pupae of 

 Glossina morsitans were found in four different parts of the forest, but 

 all of them occurred in ' sanya country '* . . . . The first pupa 

 was found at the foot of a sanya tree (Copaifera mopani). It was 

 buried in the soil about three-quarters of an inch below the surface and 

 was lying so that it almost touched the bark of the tree. The soil 

 was decidedly hard, so hard, in fact, that it was not easily broken 

 into small fragments with a trowel .... The second pupa of 

 G. morsitans was found on the same day ; and, like the first, was 

 unfortunately empty. In this instance it was lying at the foot of a 

 large tree (apparently a species of Erythrina) , or, rather, between the 

 tree trunk and a very small termites' nest, being buried in the earth 

 which had accumulated between the tree and the nest to a depth of about 



four inches from the surface The third pupa, a living one, 



was found just below the surface in a small quantity of earth which 

 had accumulated in the cavity of a large ebony tree on a level with 

 the surrounding surface soil. Here the soil, though rather hard, was 

 of a much more friable nature than that in which the pupae were found 



on the previous occasions The fourth and also perfect 



pupa was found in loose earth, which had accumulated in a deep recess 

 formed by the buttressed roots of a baobab tree (Adansonia digitata), 

 facing and exposed to the south-west. Sunlight would not, however, 



be able to enter the recess until the late afternoon, if at all 



From these observations we are of opinion that the breeding grounds 

 of Glossina morsitans in this region are thinly scattered over the whole 

 of the tsetse country, and it is quite evident that the pupae, whether 

 living or dead, do not occur in large numbers in any given spot. In 

 localities where the flies are much more numerous than they are in 



1 " The tree which preponderates in this region is the Sanya or Iron- wood 

 tree (Copaifera mopani, Kirk) ; in fact it is so abundant that those portions 

 of the forest in which it abounds are referred to as ' Sanya country,' both by 

 natives and Europeans " (Newstead, loc. cit.}. 



